I was a player, not a Judge, when the first Dungeons & Dragons Book of Lairs was published [REF3: The Book of Lairs (1986)], but one lair from that book plus my player character mixed together to dramatically impact the future of our campaign. It seemed like such a simple thing …
We were on the road between adventures, when we learned of troubles caused by a newly arrived creature of considerable ability. Certainly, the creature seemed very sure of its invincibility, as it was trivial to track its depredations back to its lair. The encounter was one of those that seemed on the edge of a Total Party Kill, but we were victorious over … one ogre mage.
What followed was entirely my fault. My character was the de facto leader of the party, and I should mention that we used my character’s Gray Elf lifespan as something of an excuse for the occasional meta-knowledge of monsters the character might have. My character said “The horn of this magical creature must surely have some value for future magical items. I will remove it while you gather the remaining treasure.” And we left.
We were successful in our next endeavor, and we returned to the City State of the Invincible Overlord for some well-deserved drunkenness and debauchery. It was during that revelry that a passing bar maid first blasted our party with a cone of cold. That hurt!
My character and I forgot that ogre magi regenerate. Except for any parts that are removed. Oops. My Judge decided that the ogre mage had become a laughing stock among his kind for losing his horn, and he would pursue my character until one of us was dead.
So, my character had the horn bejeweled with precious metals and gems, to be the finest drinking horn any adventurer might hope for. We would both prove hard to kill.
The campaign would continue to be marked by that ogre mage popping up at the most inconvenient times. My character, being effectively hunted, took on a shadow persona and established a network of safehouses, always travelling, never truly at home. Really, this suited him, as he was not a nice guy. But that’s another story, of how one little artifact can turn a campaign ...